Commit 773e8a04 authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Radim Krčmář

x86/kvm: use Enlightened VMCS when running on Hyper-V

Enlightened VMCS is just a structure in memory, the main benefit
besides avoiding somewhat slower VMREAD/VMWRITE is using clean field
mask: we tell the underlying hypervisor which fields were modified
since VMEXIT so there's no need to inspect them all.

Tight CPUID loop test shows significant speedup:
Before: 18890 cycles
After: 8304 cycles

Static key is being used to avoid performance penalty for non-Hyper-V
deployments.
Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
parent 5431390b
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